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Commit 3b9cfc0a authored by Emese Revfy's avatar Emese Revfy Committed by H. Peter Anvin
Browse files

x86, mtrr: Constify struct mtrr_ops 



This is part of the ops structure constification
effort started by Arjan van de Ven et al.

Benefits of this constification:

 * prevents modification of data that is shared
   (referenced) by many other structure instances
   at runtime

 * detects/prevents accidental (but not intentional)
   modification attempts on archs that enforce
   read-only kernel data at runtime

 * potentially better optimized code as the compiler
   can assume that the const data cannot be changed

 * the compiler/linker move const data into .rodata
   and therefore exclude them from false sharing

Signed-off-by: default avatarEmese Revfy <re.emese@gmail.com>
LKML-Reference: <4B65D712.3080804@gmail.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent ab658321

arch/x86/kernel/cpu/mtrr/amd.c

+1 −1
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ amd_validate_add_page(unsigned long base, unsigned long size, unsigned int type) 
	return 0;

}



static struct mtrr_ops amd_mtrr_ops = {

static const struct mtrr_ops amd_mtrr_ops = {

	.vendor            = X86_VENDOR_AMD,

	.set               = amd_set_mtrr,

	.get               = amd_get_mtrr,

arch/x86/kernel/cpu/mtrr/centaur.c

+1 −1
Original line number Diff line number Diff line
@@ -110,7 +110,7 @@ centaur_validate_add_page(unsigned long base, unsigned long size, unsigned int t 
	return 0;

}



static struct mtrr_ops centaur_mtrr_ops = {

static const struct mtrr_ops centaur_mtrr_ops = {

	.vendor            = X86_VENDOR_CENTAUR,

	.set               = centaur_set_mcr,

	.get               = centaur_get_mcr,

arch/x86/kernel/cpu/mtrr/cyrix.c

+1 −1
Original line number Diff line number Diff line
@@ -265,7 +265,7 @@ static void cyrix_set_all(void) 
	post_set();

}



static struct mtrr_ops cyrix_mtrr_ops = {

static const struct mtrr_ops cyrix_mtrr_ops = {

	.vendor            = X86_VENDOR_CYRIX,

	.set_all	   = cyrix_set_all,

	.set               = cyrix_set_arr,

arch/x86/kernel/cpu/mtrr/generic.c

+1 −1
Original line number Diff line number Diff line
@@ -752,7 +752,7 @@ int positive_have_wrcomb(void) 
/*

 * Generic structure...

 */

struct mtrr_ops generic_mtrr_ops = {

const struct mtrr_ops generic_mtrr_ops = {

	.use_intel_if		= 1,

	.set_all		= generic_set_all,

	.get			= generic_get_mtrr,

arch/x86/kernel/cpu/mtrr/main.c

+3 −3
Original line number Diff line number Diff line
@@ -60,14 +60,14 @@ static DEFINE_MUTEX(mtrr_mutex); 
u64 size_or_mask, size_and_mask;

static bool mtrr_aps_delayed_init;



static struct mtrr_ops *mtrr_ops[X86_VENDOR_NUM];

static const struct mtrr_ops *mtrr_ops[X86_VENDOR_NUM];



struct mtrr_ops *mtrr_if;

const struct mtrr_ops *mtrr_if;



static void set_mtrr(unsigned int reg, unsigned long base,

		     unsigned long size, mtrr_type type);



void set_mtrr_ops(struct mtrr_ops *ops)

void set_mtrr_ops(const struct mtrr_ops *ops)

{

	if (ops->vendor && ops->vendor < X86_VENDOR_NUM)

		mtrr_ops[ops->vendor] = ops;